PROJECT SUMMARY. Despite improvements in prevention and treatment, cardiovascular disease (CVD) remains the leading cause of death and disability in women. Current evidence, primarily based on self-reported data, indicates that sexual minority women (SMW; lesbian and bisexual) demonstrate significantly higher modifiable risk factors for CVD than heterosexual women (including stress, tobacco use, alcohol use, and obesity). However, little is known about factors that link sexual minority identity with CVD risk in women, which limits development of tailored prevention efforts. Although adverse life experiences (e.g., interpersonal trauma and discrimination) are posited to contribute to CVD risk in SMW, few studies have examined the potential cardiovascular effects of adverse life experiences in this population. This Career Development Award will provide Dr. Billy Caceres with the training and research skills needed to launch an independent program of research focused on identifying and mitigating the effects of stress on the association of sexual minority identity and cardiovascular health. The overall aim of this K01 application is to use a sibling design to estimate the contribution of sexual minority identity on CVD risk in women and whether this association is impacted by adverse life experiences. The proposed research is based on the scientific premise that, by accounting for unobserved familial confounding associated with CVD risk (genetics, parental factors, and childhood environment), biological heterosexual sisters will provide a strong comparison group to study CVD risk in SMW. Supported by an interdisciplinary team of mentors, Dr. Caceres will extend the Chicago Health and Life Experiences of Women (CHLEW; R01AA13328) study, the longest running study of SMW's health, to compare CVD risk among SMW enrolled in the CHLEW study (N=65) and their biological heterosexual sisters (N=65). This proposal will examine the association of sexual minority identity with: Aim 1: psychological (depressive, anxiety, and post-traumatic stress symptoms); Aim 2: behavioral (tobacco use, heavy drinking, physical activity, diet, and sleep quality); and Aim 3: physiological (cardiometabolic [body mass index, glycosylated hemoglobin, and lipids] and inflammatory [C-reactive protein and interleukin-6]) risk factors for CVD. Through coursework, seminars, experiential training, conferences, and mentored meetings, Dr. Caceres will address prior gaps in training to develop skills in: 1) women's health research, 2) behavioral cardiovascular health, 3) social epidemiology, and 4) quantitative methods for dyadic analyses. These research and training activities will inform an R01 application that will comprehensively examine physiological mechanisms that link sexual minority identity and adverse life experiences to CVD risk in women. Findings will identify modifiable psychological, behavioral, and physiological risk factors that can serve as targets for CVD prevention efforts tailored to SMW. This work provides a unique opportunity to study risk factors for CVD, a major health problem in the U.S., in a racially diverse sample of SMW and their biological heterosexual sisters.